1. Field of the Invention
This invention relates to asphaltic compositions and, in one of its aspects, relates more particularly to asphaltic compositions which exhibit improved elastic properties. Still more particularly, in this aspect, the invention relates to asphaltic compositions exhibiting improved elastic properties, durability and resistance to deterioration by oil and grease and improved adhesion to aggregate particles, and suitable for use in such applications where criteria of suppleness and high mechanical resistance must be satisfactorily met.
2. Description of the Prior Art
The use of asphalt binders for road-building and other various industrial applications, is known. These products have, however, heretofore exhibited weak elastic properties, thus limiting their use in fields where the aforementioned criteria of suppleness and high mechanical resistance are a necessary requirement. In this regard, it has, heretofore, been proposed to incorporate various additives in the asphaltic composition for increasing the desired elasticity. For such purposes, copolymers of ethylene and vinyl acetate have been proposed, for example, as disclosed in U.S. Pat. No. 3,442,841. It is found, however, that although the incorporation of copolymers of ethylene and vinyl acetate enables the elasticity of the asphalt to be increased, it also produces asphaltic compositions which present insufficient cohesion (i.e., stress necessary for a given deformation) and also weak adhesiveness. In commonly assigned U.S. Pat. No. 3,821,144 asphaltic compositions having improved cohesive properties are disclosed, comprising a major amount of asphalt, a minor amount of a synthetic terpenic resin and a copolymer of ethylene and vinyl acetate. In this respect, however, it is found that although such asphaltic compositions exhibit good elastic and cohesive properties, improved durability and resistance to deterioration by oil and grease and improved adhesion to aggregate particles are still to be desired.